The present invention relates generally to a baffle device, also known in the art as a lamella gravity separator or settler, for use in a clarifier typically used in waste treatment for gravitationally separating suspended solids from solids containing carrier liquid or fluid suspensions. The clarifiers with which the inventive baffle device is used typically consist of a circular or rectangularly-configured tank in which a centrally mounted, radially-extending arm is slowly moved or rotated about the tank at or proximate the surface of the carrier liquid.
Specifically, in waste water treatment facilities utilizing secondary clarifiers, the clarifiers' effectiveness in removing solids is perhaps the most important factor in establishing the final effluent quality of the facility. A major deterrent to effective removal is the presence of sludge density currents which cause hydraulic short circuits within the tank. These short circuits, in turn, allow solids concentrations to unintendedly bypass the tanks' clarification volume and enter the effluent. Research has shown that a peripheral baffle attached to the tank wall and directed downward at an angle into the tank can effectively minimize these density currents and properly redirect the flow into the main clarification volume, thereby improving the solids removing efficiency of the clarifier by as much as 50% or more.
The present invention provides a baffle that is mounted in cantilevered fashion along a peripheral wall of the clarifier intermediate the tank bottom and the surface of the carrier liquid contained in the tank. The inventive baffle system includes a plurality of such baffles which are constructed as modular units and form a continuous, single-surface sheet that slopes downwardly from the peripheral tank wall toward the center of the tank and terminates at a free edge suspended in spaced relation above the tank bottom.
Each of these baffles has a unitarily-integrated design that incorporates a downwardly-sloping panel member and an end bracket integrally arranged with and depending from one lateral side or end of the panel member for securing the panel member to the inwardly-facing peripheral wall surface of the clarifier tank. The second or opposite lateral end of each baffle is secured to the end bracket of the immediately-adjacent and, thereby interengaged baffle in the baffle system. Accordingly, the baffle system of the invention provides and is formed by a plurality of interengaged baffles for use in a clarifier tank and which is mounted as a single, integrated unit, each such baffle unitarily incorporating both the panel member and the cantilever mounting structure or end bracket.
Numerous clarifier and baffle configurations are disclosed in the art. However, prior art attempts have suffered from a variety of various drawbacks and deficiencies.
For example, U.S. Pat. No. 4,780,206 to Beard et al. relates to a turbulence control system for an intra-channel clarifier which reduces turbulence within and allows the removal of sludge from the clarifier. However, there is no disclosure in the reference of an improved baffle system which is constructed as a modular unit and that consists of a plurality of interengaged individual baffles, each formed as a unitarily-integrated element incorporating both the panel member and an integral end bracket for suspended securement of the baffle to the peripheral wall of the clarifier tank.
U.S. Pat. No. 4,816,157 to Jennelle is directed to an apparatus and method for clarifying solids from a solids-containing liquid having a multilayer baffle system and integral solids removal sump. The multilayer baffle system includes a first set of baffles placed above the main liquid flow path for minimizing horizontal flow and creating local turbulence so as to promote settling and assure that no solids settle on the baffles. This reference, however, does not teach the use of a baffle system constructed as a modular unit consisting of a plurality of interengaged individual baffles with each baffle incorporating both the panel member and an integrated mounting flange.
U.S. Pat. No. 5,049,278 to Galper relates to a modular plate settler for use in a liquid clarifier system having one or more inlet ports for receiving an influent flow of liquid. The modular plate settler comprises a parallelogram-shaped enclosure provided with a full bottom opening for receiving the influent flow of liquid from the settling tank. This reference, however, does not teach an improved baffle system having a plurality of baffles with each baffle consisting of a unitarily-integrated design incorporating both the panel member and the end bracket for cantilevered securement of the baffle to the peripheral wall.
Thus, none of the prior art teaches or suggests unitarily-integrated clarifier baffle and baffle system comprising a plurality of interengaged baffles for use in a clarifier tank in accordance with the teachings of the present invention. Moreover, no prior art reference discloses a plurality of interengaged individual baffles with each baffle including a panel member sloping downwardly from the tank's peripheral wall toward the tank bottom and an end bracket unitarily depending from one lateral side or end of the panel member for securing the member to the peripheral inner wall of the clarifier tank, and with the opposite lateral end of each baffle being secured to the end bracket of a next-adjacent baffle so as to define the multi-element baffle system of the invention.
It is, therefore, an object of the present invention to provide a system of plural, interengaged baffles, curved to match the peripheral contour of a circular or arcuate tank or, alternatively, linear to match the peripheral walls of a noncircular tank, and which interlock to form a rigid peripheral "shelf" or baffle system inclined inward and downward around the entire periphery of the tank.
Another object of the invention is to provide an individual baffle panel formed as a unitary, a one-piece molded unit incorporating the panel member and the end bracket.
A further object of the invention is to provide a baffle system consisting of a plurality of individual baffles, which can be readily installed in a clarifier tank, and which significantly reduces both the manufacturing time and installation process as compared to other systems.
Another object of the invention is to provide an integral bracket designed to support the cantilevered panel member at an appropriate angle to the peripheral wall of the tank while presenting a minimal surface area so as to avoid unnecessary interference with the flow of liquid within the tank.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.